摘要
既有混凝土结构加固改造中,常通过植筋技术将新增钢筋牢固锚固于原有混凝土中,以实现新旧构件的连接与整体受力。为了研究植筋锚固件的受剪性能及受力机理,考虑不同锚筋直径(12、20 mm)及不同连接方式(穿孔塞焊、螺母固定)的影响,对单向剪力作用下的预埋件、化学锚栓及植筋群锚构件受剪性能进行试验研究。结果表明:两种连接方式的植筋锚固件破坏状态均为锚筋根部钢材破坏;荷载-位移曲线呈弹性段及塑性增长段,植筋穿孔塞焊锚固件的受力机理与预埋件相似,呈双弯曲曲线;植筋螺母固定锚固件的受力机理更接近化学锚栓,为单向弯曲曲线;直径12 mm和20 mm植筋螺母固定群锚锚固件的受剪承载力分别为209.23 kN和515.50 kN,明显优于植筋穿孔塞焊锚固件(153.27 kN与426.50 kN),表明螺母固定连接的植筋具备更优的受剪性能与内力重分布能力。基于试验结果,提出了适用于HRB400钢筋的植筋螺母固定群锚构件受剪承载力计算方法,并与化学锚栓规范规定的受剪承载力计算公式进行对比,结果表明该公式计算值与实测值相比误差仅为-13.7%与-1.2%,显著优于JGJ 145—2013《混凝土结构后锚固技术规范》公式(误差-36.5%和-27.4%),验证了该方法的准确性和适用性。
In the renovation of existing concrete structures,post-installed rebar technology is widely used to anchor new steel bars into original concrete,ensuring continuity and structural integration.To study its shear performance and mechanism,comparative tests were conducted on steel embed plates,chemical anchors,and post-installed rebars under unidirectional shear.Variables included anchor bar diameters(12 mm and 20 mm)and connection methods(plug weld and nut fastening).Results showed that all the specimens fail in steel fracture at the anchor root,with load-displacement curves exhibiting elastic and plastic stages.The plug-welded post-installed rebar behaves like steel embed plates,showing double-bending curves,while the nut-fastened ones show single-bending responses similar to chemical anchors.The nut-fastened specimens with the anchor bar diameters of 12 mm and 20 mm have higher shear capacities of 209.23 kN and 515.50 kN,compared to plug-welded ones of 153.27 kN and 426.50 kN,demonstrating better shear resistance and internal force redistribution.Based on the test results,a shear capacity formula was proposed for nut-fastened post-installed rebar using HRB400 steel,and a comparison was made with the shear capacity calculation formula specified in the chemical anchor bolt specifications.The predicted values showed only-13.7%and-1.2%error relative to the test results,significantly outperforming the current code-based predictions(-36.5%and-27.4%)in JGJ 145—2013‘Technical specification for post-installed anchorage in concrete structures’.The results confirm accuracy and reliability of the proposed method.
作者
刘羽纶
徐福泉
谢剑
熊朝晖
LIU Yulun;XU Fuquan;XIE Jian;XIONG Zhaohui(School of Civil Engineering,Tianjin University,Tianjin 300350,China;China Academy of Building Research,Beijing 100013,China;Hilti(Shanghai)Ltd,Shanghai 201108,China)
出处
《建筑结构学报》
北大核心
2025年第9期253-264,共12页
Journal of Building Structures
基金
国家重点研发计划(2016YFC0701800)。
关键词
钢筋锚固
预埋件
植筋
化学锚栓
静力试验
受剪承载力
steel bar anchoring
steel embed plate
post-installed rebar
chemical anchor
static test
shear capacity
